The global tax system is broken, says Nobel prize winner

It's time for a complete overhaul of the global tax system to ensure each company pays their fair share, says Nobel laureate Joseph Stiglitz.

A group of leading economists -- led by Stiglitz -- issued a call Tuesday for countries to overhaul the system to prevent multinationals such as Apple(AAPL) and Google(GOOGL) taking advantage of loopholes to cut their tax bills.

"Multinational corporations act and therefore should be taxed as single and unified firms. It is time for our [political] leaders to be bold," Stiglitz said.

Many large companies are known to shift their profits and revenue between subsidiaries to benefit from lower taxes in certain nations, such as Ireland and Luxembourg, he said.